I hadn't noticed either problem, but then most of my text on icons I place using the Icon Text layer. In the Layers "layer", using the Text tool, did you notice that when you double-click on the "T", you can choose alignment as Centered, Left, or Right? Does this "fix" this problem for you?
As to putting glyphs on, the first glyph I tried was Yellow Light, which showed up perfectly centered on the "hand" (naturally). However, I then tried "Variant" (for some reason, both of these display on the first "page" of Glyphs when I choose this tab). This glyph appears way to the left and way above the "hand". However, the simple way to reposition it is to place it whereever it lands, then choose the "Move" tool (bottom right, two double-headed arrows and a pointer). When you place a Glyph, it lands on its own layer, and when you then select the Move tool, you can move the Glyph about on its layer, with it "following" your cursor.
I'm not sure why some icons (like Yellow Light) start centered on the hand cursor, and others (like Variant) do not -- it may be something with the size of the .png file that makes up the Glyph. Maybe if we can "figure this out", we can "fix" the off-centered glyphs to all appear "under the hand" ...
